Writing instrument



FIG. 1 is a front view of a writing instrument showing my new design;

FIG. 2 is a rear view thereof;

FIG. 3 is a side view thereof which is a mirror image of the opposite side thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a perspective view thereof which is a mirror image of the opposite perspective view thereof; and,

FIG. 7 is a perspective view thereof which is a mirror image of the opposite perspective view thereof. 

The ornamental design for a writing instrument, as shown and described. 